Clock synchronization method and apparatus, and device and storage medium

Abstract

Provided in the present application are a clock synchronization method and apparatus, and a device and a storage medium. The clock synchronization method comprises: a first node receiving first clock information sent by a second node, wherein the first clock information comprises a first timestamp and a first clock compensation parameter (S310); the first node synchronizing a local clock on the basis of the first clock information (S320); and the first node sending second clock information to a third node, wherein the second clock information comprises a second timestamp and a second clock compensation parameter, and the second timestamp is the first timestamp or the second timestamp is a timestamp determined by the first node on the basis of the first clock information (S330).

Description

Clock synchronization method, apparatus, device, and storage medium TECHNICAL FIELD

[0001] The present application relates to the field of wireless communication, in particular to a clock synchronization method, apparatus, device and storage medium. BACKGROUND

[0002] With the continuous progress of radio technology, a large number of various radio services have emerged. A traditional wireless communication network or cell generally includes a central node and multiple terminal nodes, such as the communication between a base station and multiple user terminals (UE) in a cellular network, including the 4th Generation (4G), the 5th Generation (5G), and the 6th Generation (6G).

[0003] The 3rd Generation Partnership Project (3GPP) New Radio (NR) adds time-sensitive communication (TSC) related functions in the Rel 16 standard to support time-sensitive networks (TSN) in vertical fields. The 5G network is supported as a TSN virtual bridge, a device-side TSN translator (DS-TT) module is added on the UE side, and a network-side TSN translator (NW-TT) module is added on the user plane function (UPF) side. Two TSN translators (TTs) connect the 5G network to the TSN network. As a TSN bridge, the 5G network needs to support the basic protocols related to the TSN network, including the Institute of Electrical and Electronics Engineers (IEEE) 802.1AS time synchronization protocol, etc.

[0004] Within the 5G system, the base station supports providing the UE with a timing function with 10 ns precision. The timing is provided through broadcast signaling SIB9 or unicast Radio Resource Control (RRC) signaling DLInformationTransfer. Further, the base station side or the UE side can also compensate for the link propagation delay (Propagation Delay Compensation, PDB) to complete the high-precision clock synchronization between the base station and the direct connection UE.

[0005] However, for the 3GPP system, how to complete the time synchronization between all communication nodes in a multi-hop network composed of some base stations and UEs or a wireless network composed of UEs is an urgent problem to be solved. SUMMARY

[0006] In view of this, the embodiments of the present application expect to provide a clock synchronization method, device, equipment and storage medium.

[0007] In a first aspect, the embodiments of the present application provide a clock synchronization method, comprising:

[0008] The first node receives first clock information sent by the second node, and the first clock information comprises a first timestamp and a first clock compensation parameter;

[0009] The first node synchronizes a local clock according to the first clock information;

[0010] The first node sends second clock information to the third node, and the second clock information comprises a second timestamp and a second clock compensation parameter. The second timestamp is the first timestamp or the second timestamp is a timestamp determined by the first node according to the first clock information.

[0011] In a second aspect, the embodiments of the present application provide a clock synchronization device arranged in the first node, comprising:

[0012] The receiving module is arranged to receive first clock information sent by the second node, and the first clock information comprises a first timestamp and a first clock compensation parameter;

[0013] The synchronization module is arranged to synchronize a local clock according to the first clock information;

[0014] The sending module is arranged to send second clock information to the third node, and the second clock information comprises a second timestamp and a second clock compensation parameter. The second timestamp is the first timestamp or the second timestamp is a timestamp determined by the first node according to the first clock information.

[0015] In a third aspect, the embodiments of the present application provide a clock synchronization equipment, comprising:

[0016] a memory configured to store the program;

[0017] a processor configured to execute the program, when the program is executed, performing the clock synchronization method of any implementation manner of the first aspect.

[0018] In a fourth aspect, the embodiments of the present application provide a nonvolatile storage medium, the storage medium comprising a stored program, the program performing the clock synchronization method of any implementation manner of the first aspect when executed. BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 is an industrial network topology diagram;

[0020] FIG. 2 is a schematic diagram of an application scenario of the clock synchronization method provided by the embodiments of the present application;

[0021] FIG. 3 is a flowchart of a clock synchronization method provided by the embodiments of the present application;

[0022] FIG. 4 is another schematic diagram of an application scenario of the clock synchronization method provided by the embodiments of the present application;

[0023] FIG. 5 is a schematic diagram of time delay measurement in a multi-hop network;

[0024] FIG. 6 is a schematic diagram of clock frequency ratio measurement in a multi-hop network;

[0025] FIG. 7 is a schematic diagram of the structure of a clock synchronization device provided by the embodiments of the present application;

[0026] FIG. 8 is a schematic diagram of the structure of a clock synchronization device provided by the embodiments of the present application. DETAILED DESCRIPTION

[0027] The current 5G system can achieve clock synchronization with TSN, but currently only supports the network side base station to directly connect to the UE for timing, but for complex topological networks such as industrial networks, in the case that the base station and part of the UE do not have direct connection, how to achieve time synchronization between communication nodes, there is currently no solution.

[0028] FIG. 1 is an industrial network topology diagram, and FIG. 1 shows an industrial field network topology diagram including a one-hop network. As shown in the figure, a gNB serving as a base station is directly connected with UE1 and UE1', the gNB can perform high-precision synchronization timing for UE1 and UE1', UE2 and UE2' are connected with UE1, and for the gNB, UE2 and UE2' are remote UEs, UE2 and UE2' are connected with the gNB through UE1, and this network topology can be referred to as a one-hop network. However, the gNB cannot perform high-precision synchronization timing for the non-directly connected UE2 and UE2' in the one-hop network. In FIG. 1, only a one-hop network is shown, and the same applies to a multi-hop network. However, multi-hop networks are more commonly used in the industrial field, and some devices in the industrial field need to rely on accurate clock synchronization to complete precise synchronization operations. Therefore, how to achieve high-precision clock synchronization in a multi-hop network is an important part of developing 5G network applications in the industrial network field.

[0029] In order to achieve high-precision clock synchronization of 5G network in the industrial field network, and to achieve low-latency and high-reliability deterministic communication, first, all UEs need to complete network access through the broadcast information of the base station or the discovery information of other UEs or the broadcast information of the UE, and then high-precision clock synchronization between the UE and the base station or between the UEs is achieved through the air interface.

[0030] The remote UE is indirectly connected to the network through other UEs, and the directly connected UE of the base station obtains the clock information of the network side through the reference clock information in the system information block (SIB) 9 or the unicast RRC signaling transmitted by the base station. For the remote UE, the high-precision clock of the network side needs to be obtained through the clock information transmitted by the upper-level UE.

[0031] FIG. 2 is a schematic diagram of an application scenario of a clock synchronization method provided by an embodiment of the present application. In FIG. 2, a one-hop network is taken as an example for illustration, that is, there is only one directly connected UE between the remote UE and the base station. In FIG. 2, UE1 is directly connected with the base station, and UE2 is a remote UE, and UE2 is connected with the base station through UE1. As can be seen from the figure, the base station transmits clock information (SyncMsg1) containing a network side timestamp at t1, UE1 receives the information at t2, UE1 transmits clock information (SyncMsg2) to UE2 at t3, and UE2 receives the information at t4. Based on the scenario shown in FIG. 2, the clock synchronization method provided by the embodiment of the present application is described in detail below.

[0032] FIG. 3 is a flowchart of a clock synchronization method provided by an embodiment of the present application. As shown in FIG. 2, the clock synchronization method provided by the embodiment includes the following steps:

[0033] In step S310, the first node receives the first clock information sent by the second node, and the first clock information includes the first timestamp and the first clock compensation parameter.

[0034] The clock synchronization method provided by the embodiments of the present application is applied to a first node, the first node is a node between a base station and a remote UE in a multi-hop network, the first node can be a UE directly connected to the base station, or the first node can be a remote UE, the first node receives clock information sent by an upper node (including the base station or another UE) and sends clock information to a lower node. The first node is, for example, UE1 in FIG. 2, and the second node is, for example, the base station in FIG. 2. Of course, in the multi-hop network, the second node can also be the upper UE of the first node.

[0035] First, the first node receives the first clock information sent by the second node, and the first clock information includes the first timestamp and the first clock compensation parameter. In the process of clock information transmission through the air interface and clock synchronization by the UE receiving the clock information, various parameters can affect the transmission and synchronization of the clock information. Therefore, in the process of clock synchronization, compensation for various influencing factors needs to be considered, so as to achieve accurate clock synchronization. Therefore, in the embodiments of the present application, in addition to the first timestamp for indicating the clock information, the first clock information received by the first node also includes the first clock compensation parameter, and the first clock compensation parameter includes any parameter that can affect the clock information. The first clock compensation parameter includes at least one of the first timestamp reference time, the first clock compensation value, and the first clock frequency ratio. The second node is the upper node of the first node in the multi-hop network, and the second node can be the base station or another UE. When the second node is another UE, the first timestamp and the first clock compensation parameter included in the first clock information sent by the second node can be different. The specific parameter value of the first clock compensation parameter is configured according to system requirements. The higher the required clock accuracy of the system, the more clock compensation parameters need to be considered. Or the first clock compensation parameter is determined according to the actual deployment of the system. For example, when the distance between the nodes in the multi-hop network is relatively close, the air interface delay of the clock information transmission can be ignored, so there is no need to consider the air interface delay of the clock information. When the distance between the nodes in the multi-hop network is relatively far, the air interface delay of the clock information transmission has a greater impact, and the air interface delay needs to be considered when the clock accuracy requirement is high.

[0036] In an embodiment, the first timestamp is an original timestamp representing a specific reference time sent by a network grand master node, or the first timestamp is a timestamp at which the first timestamp is transmitted after the second node completes clock synchronization, or the first timestamp is a timestamp at which a specific reference time is located after the second node completes clock synchronization. Clocks in a 5G network are issued by a grand master node, and the grand master node sends clock information to each base station. For the first node, the first timestamp received from the second node can be an original timestamp representing a specific reference time sent by a network grand master node, that is, each node from the base station to the first node directly forwards the first timestamp sent by the grand master node. Or the first timestamp received by the first node is a timestamp at which the first timestamp is transmitted after the second node completes clock synchronization, that is, the second node first performs clock synchronization according to the clock information sent by the grand master node, then generates and sends the first timestamp, and the first timestamp is a timestamp at which the first timestamp is sent. Or the first timestamp received by the first node is a timestamp at which a specific reference time is located after the second node completes clock synchronization, that is, the second node first performs clock synchronization according to the clock information sent by the grand master node, then determines a specific reference time corresponding to the first timestamp according to a preset rule and sends the first timestamp.

[0037] In step S320, the first node synchronizes the local clock according to the first clock information.

[0038] The first node synchronizes the local clock according to the first timestamp and the first clock compensation parameter after receiving the first clock information. As can be seen from FIG. 2, the base station sends the clock information at time t1, and the UE1 receives the information at time t2, that is, the time at which the second node sends the first clock information can be different from the time at which the first node receives the first clock information, and there is a certain time difference, which can be caused by the transmission characteristics of the communication system or the air interface delay of data transmission. The first timestamp in the first clock information is an information containing absolute time, and therefore the first node needs to compensate the first timestamp according to the time difference between the time at which the first clock information is received and the time at which the first clock information is sent by the second node, so as to obtain accurate clock information and thereby synchronize the local clock. In addition, the local clocks of different communication nodes are determined according to the local reference clock signal, and the local reference clock signal is determined according to the frequency of the local crystal oscillator. Since the frequencies of different local crystal oscillators cannot be completely consistent, the local clocks of different nodes can be out of synchronization after a period of time, and therefore the compensation of the first timestamp can also consider the clock frequency ratio of the local clock frequency and the network side clock frequency. In summary, the first node calculates the clock compensation value of the first timestamp according to different first clock compensation parameters, and adds the clock compensation value to the first timestamp, so as to obtain accurate clock value, thereby synchronizing the local clock, and achieving accurate clock synchronization.

[0039] In step S330, the first node sends second clock information to the third node, the second clock information including a second timestamp and a second clock compensation parameter, the second timestamp being the first timestamp or a timestamp determined by the first node according to the first clock information.

[0040] After the first node completes clock synchronization, the first node sends second clock information to a third node, the second clock information including a second timestamp and a second clock compensation parameter. The third node is a next-level node of the first node, for example, UE2 in FIG. 2, and the third node has no direct connection with the base station, and the third node needs to perform clock synchronization according to the clock information sent by the first node. The second clock information sent by the first node to the third node also includes a timestamp and a corresponding clock compensation parameter, where the second timestamp is the first timestamp or the second timestamp is a timestamp determined by the first node according to the first clock information. The first node sends clock information to the third node in two ways. In the first way, the first node directly sends the first timestamp received from the second node to the third node, that is, the second timestamp is the first timestamp, and at this time, the second clock compensation parameter is the total clock compensation parameter of the transmission path from the second node to the third node, or the second clock compensation parameter is the total clock compensation parameter of the transmission path from the base station to the third node, and the third node can compensate the received first timestamp according to the received second clock compensation parameter to obtain accurate clock information. In the second way, the first node calculates the second timestamp according to the first clock compensation parameter, the second clock compensation parameter is the clock compensation parameter of the transmission path from the first node to the third node, and the third node can compensate the received second timestamp according to the received second clock compensation parameter to obtain accurate clock information. In short, no matter in which case, the first node can send a timestamp and a corresponding clock compensation parameter to the third node, and the third node can calculate accurate clock information according to the received timestamp and clock compensation parameter, so as to perform clock synchronization on the local clock of the third node.

[0041] Similarly to the first clock compensation parameter, the second clock compensation parameter includes at least one of a second timestamp reference time, a second clock compensation value, and a second clock frequency ratio.

[0042] Similarly to the first timestamp, the second timestamp is an original timestamp sent by the network master clock node representing a specific reference time, or the second timestamp is a timestamp at the time when the first node transmits the first timestamp after completing clock synchronization, or the second timestamp is a timestamp at a specific reference time after the first node completes clock synchronization.

[0043] The clock synchronization method provided in this embodiment can make each node in the multi-hop network achieve accurate clock synchronization after the first node receives the first clock information including the first timestamp and the first clock compensation parameter sent by the second node, performs synchronization of the local clock, and then sends the second clock information including the second timestamp and the second clock compensation parameter to the third node, thereby providing an accurate clock synchronization basis for the application of the 5G network in the industrial multi-hop network requiring accurate clock synchronization.

[0044] In an embodiment, if the first clock compensation parameter includes a first time stamp reference time, then the first time stamp is the time stamp of the first time stamp reference time, otherwise the first time stamp is the time stamp of the time when the first clock information is sent. That is, the second node can specify a first time stamp reference time and send the time stamp of the first time stamp reference time as the first time stamp, or the second node can send the time when the first time stamp is sent as the first time stamp reference time. The first node determines the time stamp of the first time stamp according to whether the first time stamp reference time is included in the received first clock compensation parameter. Correspondingly, if the second clock compensation parameter includes a second time stamp reference time, then the second time stamp is the time stamp of the second time stamp reference time, otherwise the second time stamp is the time stamp of the time when the second clock information is sent.

[0045] In an embodiment, if the first clock compensation parameter includes a first clock compensation value, it indicates that the first node needs to perform clock compensation on the first time stamp, and the first clock compensation value includes the sum of the clock message residence time of each node between the time when the first time stamp is located and the second node. When the first time stamp is the time stamp sent by the base station, that is, the first time stamp is only forwarded from the base station to the second node, the sum of the clock message residence time of each node between the base station and the second node is the sum of the clock message residence time of each node, because the first time stamp will have a certain residence time when it arrives at each node, which can be the data processing time after the node receives the first time stamp, or the preset data sending interval from the time when the node receives the first time stamp to the time when the first time stamp is sent, or the time required for the node to receive the retransmitted first time stamp, etc. When the second node is the base station, the first clock message does not reside in any node, so the first clock compensation value will be zero. When the first time stamp is the time stamp sent by the second node, the first clock compensation value is the sum of the clock message residence time of each node from the second node to the second node, which also means that the first clock compensation value is zero. Similarly, if the second clock compensation parameter includes a first clock compensation value, the second clock compensation value includes the sum of the clock message residence time of each node between the time when the second time stamp is located and the first node. The second clock compensation value is similar to the first clock compensation value, which will not be described here. In addition, as shown in FIG. 2, when UE1 sends the clock message to UE2, because the time when the clock message is received from the base station is t2 and the time when the clock message is sent to UE2 is t3, the residence time of the clock message sent by UE1 to UE2 is t3-t2, that is, the second clock compensation parameter is t3-t2.

[0046] In an embodiment, if the distance between each node in the multi-hop network is far, the link propagation delay of the clock message transmitted between each node can also be considered in addition to the clock compensation value of the clock message. Based on the configuration signaling, or the indication of the pre-configuration signaling or dynamic indication signaling, whether the link propagation delay is included in the first clock compensation value is considered. The first clock compensation value further includes the sum of the link propagation delay between each node between the time point of the first timestamp and the second node, or the first clock compensation value further includes the sum of the link propagation delay between each node between the time point of the first timestamp and the first node. When the first timestamp is the timestamp sent by the base station, that is, the first timestamp is only forwarded from the base station to the second node, the sum of the link propagation delay of the first timestamp is the sum of the link propagation delay between each node from the base station to the second node, because the first timestamp will have a certain link propagation delay when it arrives at each node. When the second node is the base station, the time point of the first timestamp in the first clock message is determined at the second node, so the first clock compensation value will be zero. When the first timestamp is the timestamp sent by the second node, the first clock compensation value is the transmission delay of the clock message from the second node to the second node, which means that the first clock compensation value is zero. Or the first node can also compensate the propagation delay between the second node and the first node when performing clock synchronization, that is, the sum of the link propagation delay between each node between the time point of the first timestamp and the first node. Similarly, the second clock compensation value further includes the sum of the link propagation delay between each node between the time point of the second timestamp and the first node, or the second clock compensation value further includes the sum of the link propagation delay between each node between the time point of the second timestamp and the third node. The sum of the link propagation delay included in the second clock compensation value is similar to the first clock compensation value, which will not be described here. In addition, as shown in FIG. 2, when UE1 sends the clock message to UE2, because the time point of receiving the clock message from the base station is t2, and the time point of sending the clock message to UE2 is t3, the residence time of the clock message sent by UE1 to UE2 is t3-t2, and the air interface transmission delay of the clock message sent by the base station to UE1 is PD1, that is, the second clock compensation parameter is t3-t2+PD1.

[0047] After the first node determines the first clock compensation value, it can synchronize the local clock according to the first timestamp and the first clock compensation value. The first clock compensation value is actually measured by the second node and sent to the first node, that is, the second node measures the upper node of the second node, and if the second node is a base station, the first clock compensation value is generally zero. The second clock compensation value is measured by the first node to the upper node of the first node, and the second clock compensation value is sent to the third node, so that the third node performs clock synchronization. If the second node as the upper node of the first node is a base station, the second clock compensation value is the relevant clock compensation parameter between the first node and the second node, and if the second node is also a UE, the second clock compensation value is the relevant clock compensation parameter between the first node and the second node. At this time, if the upper node of the second node is also a UE instead of a base station, if the second timestamp sent by the first node to the third node is the same as the first timestamp, the second clock compensation parameter sent by the first node to the third node is the cumulative clock compensation parameter, that is, the clock related compensation parameters of each node between the base station and the first node need to be sent to the third node, so that the third node can perform clock synchronization according to the cumulative clock compensation parameter; if the second timestamp sent by the first node to the third node is different from the first timestamp, but is the corrected timestamp calculated by the first node, then the second clock compensation parameter sent by the first node to the third node is the relevant clock compensation parameter between the second node and the first node.

[0048] In an embodiment, when determining the first clock compensation value, the second node can also consider the ratio of the clock frequencies between the network master clock node and the second node, that is, the second node considers the first clock frequency ratio when calculating the first clock compensation value. The first clock frequency ratio is the ratio of the clock frequencies of the network master clock node and the second node. The second node takes the product of the determined first clock compensation value and the clock frequency ratio as a new first clock compensation value. In this way, after the second node sends the clock compensation value to the first node, the first node can directly synchronize the local clock according to the sum of the first timestamp and the first clock compensation value, and the first node does not need to consider the clock frequency ratio between the network master clock node and the second node. Correspondingly, in the second clock compensation parameter, the product of the second clock compensation value and the second clock frequency ratio is taken as a new second clock compensation value, that is, the first node can also take the product of the determined second clock compensation value and the second clock frequency ratio as a new second clock frequency compensation value. The second clock frequency ratio is the ratio of the clock frequencies of the network master clock node and the first node.

[0049] In an embodiment, if the first clock compensation parameter comprises a first clock frequency ratio, the first node synchronizes the local clock according to the first clock information, comprising: the first node synchronizes the local clock according to the first timestamp, the first clock compensation value and the first clock frequency ratio, wherein the first clock frequency ratio is a ratio of the clock frequency of the network grandmaster clock node to the clock frequency of the first node, or the first clock frequency ratio is a ratio of the clock frequency of the network grandmaster clock node to the clock frequency of the second node. That is, the first clock frequency ratio notified by the second node to the first node can consider the clock frequency ratio of the node before the network grandmaster clock node and the first node, and can further consider the clock frequency ratio between the network grandmaster clock node and the first node. Since the local clock frequencies of the nodes in the multi-hop network can be different, the clock compensation accuracy of the first timestamp according to the first clock compensation value can still not be very accurate, so in the embodiment of the application, the first timestamp can be clock compensated according to the first clock frequency ratio. The first clock frequency ratio is a ratio of the clock frequency of the network grandmaster clock node relative to the second node, or the first clock frequency ratio is a ratio of the clock frequency of the network grandmaster clock node relative to the first node, and the first clock frequency ratio is 1 if the second node is a base station. Correspondingly, if the second clock compensation parameter comprises a second clock frequency ratio, the third node synchronizes the local clock according to the second timestamp, the second clock compensation value and the second clock frequency ratio, wherein the second clock frequency ratio is a ratio of the clock frequency of the network grandmaster clock node to the clock frequency of the first node, or the second clock frequency ratio is a ratio of the clock frequency of the network grandmaster clock node to the clock frequency of the third node. As shown in FIG. 2, when UE1 sends the clock message to UE2, since the time of receiving the clock message from the base station is t2, and the time of sending the clock message to UE2 is t3, the residence time of the clock message sent by UE1 to UE2 is t3-t2, and considering the air interface transmission delay of the clock message sent by the base station to UE1 is PD1, that is, the second clock compensation parameter is t3-t2+PD1, and the clock frequency ratio of the network grandmaster clock node to UE1 is d1, then UE2 synchronizes the local clock according to the second timestamp and (t3-t2+PD1)*d1.

[0050] The first clock frequency ratio and the second clock frequency ratio can comprise different contents, and the contents of the first clock frequency ratio or the second clock frequency ratio are determined based on configuration signaling, or pre-configuration signaling or dynamic indication signaling.

[0051] In an embodiment, the first node synchronizes the local clock according to the first timestamp, and the first clock compensation value, the first clock frequency ratio, and the third clock frequency ratio based on the configuration signaling, or the pre-configuration signaling or the dynamic indication signaling. In addition to the first clock frequency ratio and the second clock frequency ratio, the third clock frequency ratio can also be introduced, the first clock frequency ratio and the second clock frequency ratio are both the clock frequency ratio between the network master clock node and each node, and the third clock frequency ratio is the ratio of the clock frequency of the second node to the clock frequency of the first node. When the first clock frequency ratio included in the first clock compensation parameter sent by the second node to the first node is the clock frequency ratio between the network master clock node and the second node, the first node can also consider the clock frequency ratio between the second node and the first node, that is, the third clock frequency ratio, when synchronizing the local clock, and additionally multiply the third clock frequency ratio when calculating. The third clock frequency ratio can be measured by the second node or measured by the first node. Correspondingly, the second clock frequency ratio is the product of the first clock frequency ratio and the third clock frequency ratio, that is, when the first clock frequency ratio is the clock frequency ratio between the network master node and the second node, the product of the first clock frequency ratio and the third clock frequency ratio is taken as the second clock frequency ratio, that is, the clock frequency ratio between the network master clock node and the first node. As shown in FIG. 2, when UE1 sends the clock message to UE2, because the time of receiving the clock message from the base station is t2, and the time of sending the clock message to UE2 is t3, the residence time of the clock message sent by UE1 to UE2 is t3-t2, and considering that the air interface transmission delay of the clock message sent by the base station to UE1 is PD1, that is, the second clock compensation parameter is t3-t2+PD1, and the clock frequency ratio between the network master clock node and UE1 is d1, UE2 synchronizes the local clock according to the second timestamp and (t3-t2+PD1)*d1. The accurate clock of UE2 at any time t after t4 when receiving the clock message sent by UE1 can be = second timestamp + (t3-t2+PD1)*d1 + (t-t4+PD2)*d1*d2, wherein PD2 is the air interface transmission delay of the clock message sent by UE1 to UE2, and d2 is the clock frequency ratio between UE1 and UE2 measured by UE2.

[0052] In an embodiment, when the first clock information comprises a first clock compensation value, the first node synchronizes the local clock according to the first clock information, which can be adding the first timestamp sent by the second node and the first clock information as an absolute time to synchronize the local clock. The first clock compensation value in the first clock information sent by the second node to the first node can only consider the time delay influence from the base station to the second node, or can further consider the time delay influence between the second node and the first node. If the first clock compensation value sent by the second node only comprises the time delay influence from the base station to the second node, the first node can or can not consider the time delay influence between the second node and the first node when performing clock synchronization. In addition, the first node can synchronize different time instants when performing clock synchronization. Specifically, the following four different clock synchronization cases of the first node are described in detail. 1. The first node synchronizes the time of the local clock reference time instant according to at least one of the first timestamp, the first clock compensation value and the link propagation delay between the second node and the first node. 2. The first node synchronizes the time of the time instant when the first clock information is received by the local clock according to at least one of the first timestamp, the first clock compensation value and the link propagation delay between the second node and the first node. 3. Or the first node synchronizes the time of any time instant after the local clock reference time instant according to at least one of the first timestamp, the first clock compensation value, the first node local time difference, the first clock frequency ratio, the second node and the first node between the clock frequency ratio, the link propagation delay between the second node and the first node, wherein the first node local time difference is the time difference between any time instant after the local clock reference time instant and the local clock reference time instant determined by the first node according to the local clock. 4. The first node synchronizes the time of any time instant after the time instant when the first clock information is received by the local clock according to at least one of the first timestamp, the first clock compensation value, the first node local time difference, the first clock frequency ratio, the second node and the first node between the clock frequency ratio, the link propagation delay between the second node and the first node, wherein the first node local time difference is the time difference between any time instant after the local clock reference time instant and the local clock reference time instant determined by the first node according to the local clock. In the above different cases, the first node determines the way of synchronizing the time of the local clock reference time instant or the time of the time instant when the first clock information is received by the local clock or the time of any time instant after the local clock reference time instant or the time of any time instant after the time instant when the first clock information is received by the local clock based on configuration signaling, or pre-configuration signaling, or pre-defined rules, or dynamic signaling.

[0053] In an embodiment, when the UE sends the clock information to the next level UE, one of the information to be informed is the ratio of the base station clock frequency to the current UE clock, the reference clock in the 5G system can be the base station clock, the reference clock can also be other clock sources, such as Global Positioning System (GPS), Operation Administration and Maintenance (OAM) configured network entity, clock server, clock source UE, etc., in this way, the clock frequency ratio can be understood as the ratio of the reference clock frequency to the current UE clock frequency. This ratio will increase with the increase of the number of adjustments.

[0054] In an embodiment, the first node receives the first clock information sent by the second node through the first signaling, and the first node sends the second clock information to the third node through the second signaling; wherein the first signaling or the second signaling is a Media Access Control (MAC CE) signaling or a RRC signaling. Wherein the first signaling or the second signaling is any one of broadcast signaling, groupcast signaling or unicast signaling, the first signaling is periodically sent or sent according to the trigger of the first node, and the second signaling is periodically sent or sent according to the trigger of the third node. The clock information between the nodes can be periodically sent, for the system with high requirement for clock synchronization accuracy, the clock information can be sent between the nodes at a certain period, that is, the nodes perform clock synchronization according to a certain preset period, and the sending period of the clock information can be set according to the system requirement. Or the clock information between the nodes can be sent according to the trigger of the next level node, that is, the next level node can send a clock synchronization request to the upper level node, and the upper level node sends the clock information to the next level node, which can save the system overhead required for sending the clock information.

[0055] According to the clock synchronization method provided by the embodiment shown in FIG. 3, the clock synchronization method provided by the embodiment of the present application realizes the clock synchronization of each node in the multi-hop network through the transmission of the always information. In summary, the clock synchronization method provided by the embodiment of the present application can be divided into two categories. One is that the first node as an intermediate node forwards the timestamp received from the second node to the third node. For example, in the system shown in FIG. 2, UE1 can obtain the accurate clock of UE1 at t2 according to the clock information received at t2. The clock information forwarded by UE1 to UE2 at t3 includes at least one of the following: the timestamp of the network side (originTimeStamp), the clock information residence time at UE1 (t3-t2), the base station clock frequency and the clock frequency ratio of UE1 (optionally, the base station to UE1 link propagation delay PD is also included). UE2 can obtain the accurate clock of UE2 at t4 according to the clock information transmitted by UE1 at t4. Optionally, the air interface delay from UE1 to UE2 can be further considered to make the accurate clock calculated by UE2 at t4 more accurate.

[0056] The other is that the first node as an intermediate node calculates the accurate second timestamp after receiving the first timestamp sent by the second node and sends the second timestamp to the third node. For example, in the system shown in FIG. 2, UE1 can obtain the accurate clock of UE1 at t2 according to the clock information received at t2. UE1 calculates the accurate clock NewTimeStamp at t3 according to the accurate clock information at t2 and the clock frequency ratio of the base station and UE1 (optionally, the base station to UE1 link propagation delay PD is also included). The clock information forwarded by UE1 to UE2 at t3 includes at least one of the following: the updated timestamp (NewTimeStamp), the clock frequency ratio of the base station relative to UE1. UE2 can obtain the accurate clock of UE2 at t4 according to the clock information transmitted by UE1 at t4 (optionally, the link propagation delay PD from UE1 to UE2 is also included).

[0057] For a multi-hop network including two UEs, the clock synchronization method provided by the embodiments of the present application can also be classified into two categories according to the above method, which are as follows: 1. The upper-level UE of the remote UE forwards the clock information from the base station to the remote UE. The information that needs to be sent by the upper-level UE of the remote UE to the remote UE includes at least one of the following: the original clock information originTimeStamp from the network side, the ratio of the clock frequency of the base station to the clock frequency of the upper-level UE of the remote UE, and the information residence time between the sending of the clock information of the base station and the sending of the clock information of the upper-level UE of the remote UE (the residence time can include the link propagation delay of each air interface link between the base station and the upper-level UE of the remote UE). 2. The upper-level UE of the remote UE regenerates the clock information according to the received clock information of the upper-level node and sends it to the remote UE. The information that needs to be sent by the upper-level UE of the remote UE to the remote UE includes at least one of the following: the accurate clock information NewTimeStamp of the upper-level UE of the remote UE and the ratio of the clock frequency of the base station to the clock frequency of the upper-level UE of the remote UE.

[0058] The clock synchronization method provided by the embodiments of the present application is further described below with several specific embodiments.

[0059] Embodiment one: the upper-level UE of the remote UE forwards the clock information from the base station to the remote UE

[0060] Example 1: one-hop network and without considering air interface link propagation delay

[0061] The network structure of the one-hop network is shown in FIG. 2. The base station sends the clock information to UE1 at t1, which contains the time stamp originTimeStamp1 of the network side. UE1 receives the clock information at t2. UE1 sends the clock information at t3, which contains the time stamp originTimeStamp1 of the network side and the residence time (t3-t2)*d1, where d1 is the ratio of the clock frequency of the base station to the clock frequency of UE1 measured by UE1.

[0062] UE2 receives the clock information sent by UE1 at t4. Therefore, the accurate clock of UE2 at the local t4 is equal to originTimeStamp1+(t3-t2)*d1.

[0063] The accurate clock of UE2 at any time t after the local t4 is equal to originTimeStamp1+(t3-t2)*d1+(t-t4)*d2*d1, where d2 is the ratio of the clock frequency of UE1 to the clock frequency of UE2 measured by UE2.

[0064] Example 1-2: two-hop network and without considering air interface link propagation delay

[0065] Figure 4 is another application scenario of the clock synchronization method provided by the embodiment of the present application, and Figure 4 takes a two-hop network as an example, that is, there are two direct connection UEs between the remote UE and the base station. In Figure 4, UE1 is directly connected with the base station, and UE2 and UE3 are remote UEs, UE2 is connected with the base station through UE1, and UE3 is connected with UE1 through UE2. As can be seen from the figure, the base station sends the clock information (SyncMsg1) containing the network side timestamp at t1, UE1 receives the information at t2, UE1 sends the clock information (SyncMsg2) to UE2 at t3, UE2 receives the information at t4, and UE2 sends the clock information (SyncMsg3) to UE3 at t5, and UE3 receives the information at t6.

[0066] The base station sends the clock information to UE1 at t1, the clock information contains the network side timestamp originTimeStamp1, UE1 receives the clock information at t2, UE1 sends the clock information at t3, the clock information contains the network side timestamp originTimeStamp1 and the residence time (t3-t2)*d1, wherein d1 is the ratio of the clock frequency of the base station measured by UE1 to the clock frequency of UE1.

[0067] UE2 receives the clock information sent by UE1 at t4, and the clock of UE2 at any time after t4 is equal to originTimeStamp1+(t3-t2)*d1+(t-t4)*d1*d2.

[0068] UE2 sends the clock information at t5, the clock information contains the network side timestamp originTimeStamp1 and the residence time (t3-t2)*d1+(t5-t4)*d1*d2, wherein d1 is the ratio of the clock frequency of the base station measured by UE1 to the clock frequency of UE1, and d2 is the ratio of the clock frequency of UE1 measured by UE2 to the clock frequency of UE2.

[0069] Then, the accurate clock of UE3 at local t6 is equal to originTimeStamp1+(t3-t2)*d1+(t5-t4)*d1*d2.

[0070] UE3's accurate clock at any time t after the local time t6 = originTimeStamp1 + (t3-t2)*d1 + (t5-t4)*d1*d2 + (t-t6)*d1*d2*d3, where d2 is the ratio of UE1's clock frequency to UE2's clock frequency as measured by UE2, and d3 is the ratio of UE2's clock frequency to UE3's clock frequency as measured by UE3.

[0071] The above describes the case where the air interface delay between UE1 and UE2 or the ratio of clock frequencies between UE1 and UE2 is only considered at UE2. If UE1 itself considers the air interface delay between UE1 and UE2 or the ratio of clock frequencies between UE1 and UE2, then UE1 informs UE2 of the clock compensation value = (t3-t2+PD)*(ratio of clock frequencies from the master clock node to UE1). The ratio of clock frequencies that UE1 informs UE2 = ratio of clock frequencies from the master clock node to UE2 = ratio of clock frequencies from the master clock node to UE1 * ratio of clock frequencies from UE2 to UE1. Further, UE2's clock at time t4 = originTimeStamp1 + (t3-t2+PD)*(ratio of clock frequencies from the master clock node to UE1). UE2's clock at any time t after time t4 = originTimeStamp1 + (t3-t2+PD)*(ratio of clock frequencies from the master clock node to UE1) + (t-t4)*(ratio of clock frequencies from the master clock node to UE2). Where PD is the air interface propagation delay between UE1 and UE2 as measured by UE1.

[0072] Example 2: One-hop network considers air interface link propagation delay

[0073] The base station sends clock information to UE1 at time t1, the clock information containing the network-side timestamp originTimeStamp1, UE1 receives the clock information at time t2, UE1 sends clock information at time t3, the clock information containing the network-side timestamp originTimeStamp1 and the correction time (t3-t2+PD1)*d1, where d1 is the ratio of the base station's clock frequency to UE1's clock frequency as measured by UE1, and PD1 is the air interface transmission delay between the base station and UE1.

[0074] UE2 receives the clock information sent by UE1 at time t4, then UE2's accurate clock at the local time t4 = originTimeStamp1 + (t3-t2+PD1)*d1 + PD2*d2*d1.

[0075] The accurate clock of UE2 at any time t after the local time t4 is equal to originTimeStamp1 + (t3-t2+PD1)*d1 + (t-t4+PD2)*d2*d1, where d2 is the ratio of the clock frequency of UE1 measured by UE2 to the clock frequency of UE2, and PD2 is the air interface transmission delay between UE1 and UE2.

[0076] The method of two-hop or multi-hop network considering air interface link propagation delay is similar, which is not described here.

[0077] In the second embodiment, the upper-level UE of the remote UE regenerates the clock information according to the received clock information of the upper-level node and sends it to the remote UE

[0078] Example 1: One-hop network and without considering air interface link propagation delay

[0079] The base station sends the clock information to UE1 at time t1, which contains the time stamp originTimeStamp1 of the network side, UE1 receives the clock information at time t2, UE1 sends the clock information at time t3, which contains the accurate time stamp NewTimeStamp1 and the ratio d1 of the base station clock frequency to the UE1 clock frequency.

[0080] NewTimeStamp1 = originTimeStamp1 + (t3-t2)*d1.

[0081] UE2 receives the clock information sent by UE1 at time t4, and the accurate clock of UE2 at the local time t4 is equal to NewTimeStamp1.

[0082] The accurate clock of UE2 at any time t after the local time t4 is equal to NewTimeStamp1 + (t-t4)*d2*d1, where d2 is the ratio of the clock frequency of UE1 measured by UE2 to the clock frequency of UE2.

[0083] Example 1-2: Two-hop network and without considering air interface link propagation delay

[0084] The network structure of two-hop network is shown in FIG. 4, the base station sends the clock information to UE1 at time t1, which contains the time stamp originTimeStamp1 of the network side, UE1 receives the clock information at time t2, UE1 sends the clock information at time t3, which contains the accurate time stamp NewTimeStamp1 and the ratio d1 of the base station clock frequency to the UE1 clock frequency.

[0085] NewTimeStamp1 = originTimeStamp1 + (t3-t2) * d1.

[0086] UE2 receives the clock information sent by UE1 at time t4, then the accurate clock of UE2 at local time t4 = ewTimeStamp1.

[0087] UE2 sends the clock information at time t5, the clock information contains accurate time stamp NewTimeStamp2, and the ratio of base station clock frequency to UE2 clock frequency d1*d2.

[0088] NewTimeStamp2 = originTimeStamp1 + (t3-t2) * d1 + (t5-t4) * d1*d2.

[0089] UE3 receives the clock information sent by UE2 at time t6, then the accurate clock of UE3 at local time t6 = NewTimeStamp2.

[0090] The accurate clock of UE3 at any time t after local time t6 = NewTimeStamp2 + (t-t6) * d1*d2*d3, where d2 is the ratio of UE1 clock frequency to UE2 clock frequency measured by UE2, and d3 is the ratio of UE2 clock frequency to UE3 clock frequency measured by UE3.

[0091] Example 2: One-hop network considering air interface link propagation delay

[0092] The base station sends the clock information to UE1 at time t1, the clock information contains network side time stamp originTimeStamp1, UE1 receives the clock information at time t2, UE1 sends the clock information at time t3, the clock information contains accurate time stamp NewTimeStamp1, and the ratio of base station clock frequency to UE1 clock frequency d1.

[0093] NewTimeStamp1 = originTimeStamp1 + (t3-t2+PD1) * d1.

[0094] UE2 receives the clock information sent by UE1 at time t4, then the accurate clock of UE2 at local time t4 = ewTimeStamp1.

[0095] The accurate clock of UE2 at any time t after local time t4 = NewTimeStamp1 + (t-t4+PD2) * d2*d1, where d2 is the ratio of UE1 clock frequency to UE2 clock frequency measured by UE2.

[0096] Example 2 has another processing method:

[0097] It should be noted that when considering the propagation delay of each link, the PD can also be compensated at UE1, at which time the clock stamp of UE1 at the local t3 time of sending

[0098] NewTimeStamp1' = originTimeStamp1 + (t3-t2+PD1)*d1+PD2*d2*d1.

[0099] Then the accurate clock of UE2 at any time t after the local t4 time = NewTimeStamp1' + (t-t4)*d2*d1, where d2 is the ratio of the clock frequency of UE1 measured by UE2 to the clock frequency of UE2.

[0100] For any two nodes directly connected in a multi-hop network, such as the base station to UE1, UE1 to UE2, and UE2 to UE3 in FIG. 4, the air interface delay delay between them is measured by a reference signal or data signal on the air interface, and the clock frequency ratio of the previous node and itself.

[0101] FIG. 5 is a schematic diagram of delay measurement in a multi-hop network, as shown in FIG. 5, UE2 sends a delay measurement request to UE1 at t1, UE1 receives the delay measurement request at t2, UE1 sends a delay measurement feedback to UE2 at t3, and UE2 receives the experimental measurement feedback at t4.

[0102] If the influence of the clock frequency of different nodes is not considered, then the air interface delay delay between UE1 and UE2 measured by UE2 = [(t4-t1)-(t3-t2)] / 2.

[0103] FIG. 6 is a schematic diagram of clock frequency ratio measurement in a multi-hop network, as shown in FIG. 6, UE1 sends first information to UE2 at t1, UE2 receives the first information at t1', UE1 sends second information to UE2 at t2, and UE2 receives the second information at t2'. UE2 calculates the clock frequency ratio according to the transmission and reception times of the first information and the second information.

[0104] The clock frequency ratio R of UE1 relative to UE2 measured by UE2 = (t1'-t1) / (t2'-t2). If the ratio = 1, it means that the clock frequencies of UE1 and UE2 are the same, if the ratio < 1, it means that the clock of UE2 runs faster, and if the ratio > 1, it means that the clock of UE2 runs slower.

[0105] Further, if the clock frequency is considered to affect the air interface delay calculation, the air interface delay of UE1 to UE2 measured by UE2 in Figure 5 = [R*(t4-t1)-(t3-t2)] / 2.

[0106] The delay and clock ratio can also be measured at UE1, and the measurement method is similar to the above description.

[0107] Figure 7 is a structural schematic diagram of a clock synchronization device provided by an embodiment of the present application. As shown in Figure 7, the clock synchronization device provided by the embodiment includes:

[0108] The receiving module 71 is configured to receive the first clock information sent by the second node, and the first clock information includes the first timestamp and the first clock compensation parameter; the synchronization module 72 is configured to synchronize the local clock of the first node according to the first clock information; and the sending module 3 is configured to send the second clock information to the third node by the first node, and the second clock information includes the second timestamp and the second clock compensation parameter, and the second timestamp is the first timestamp or the second timestamp is the timestamp determined by the first node according to the first clock information.

[0109] The clock synchronization device provided by the embodiment is arranged at the first node acting as an intermediate node in the multi-hop network, and is used to execute the clock synchronization method of the embodiment shown in Figure 3, and the implementation principle and technical effects are similar, which will not be described here.

[0110] Figure 8 is a structural schematic diagram of a clock synchronization device provided by an embodiment of the present application. As shown in Figure 8, the service node selection device includes a processor 81, a memory 82, a receiver 83 and a transmitter 84; the number of processors 81 in the clock synchronization device can be one or more, and one processor 81 is taken as an example in Figure 8; the processor 81, the memory 82, the receiver 83 and the transmitter 84 in the clock synchronization device can be connected through a bus or other means, and the connection through the bus is taken as an example in Figure 8.

[0111] The memory 842 is a computer readable storage medium, which can be used to store software programs, computer executable programs and modules, such as the program instructions / modules (the receiving module 71, the synchronization module 72 and the sending module 73) corresponding to the clock synchronization method in the embodiment of the present application. The processor 81 runs the software programs, instructions and modules stored in the memory 82, so as to realize the various functions and data processing of the clock synchronization device, that is, to realize the clock synchronization method described above.

[0112] The memory 82 can mainly include a program storage area and a data storage area. The program storage area can store an operating system and application programs required by at least one function. The data storage area can store data created according to the use of the clock synchronization device, and the like. In addition, the memory 82 can include a high-speed random access memory, and can also include a nonvolatile memory such as at least one of a magnetic disk storage device, a flash memory device, or other nonvolatile solid-state memory device.

[0113] The receiver 83 is any device / module with data receiving capability or a combination of devices / modules with data receiving capability. The transmitter 84 is any device / module with data sending capability or a combination of devices / modules with data sending capability.

[0114] The embodiment of the present application further provides a storage medium containing computer executable instructions, which, when executed by a computer processor, are used to perform a clock synchronization method. The method comprises the following steps: a first node receives first clock information sent by a second node, wherein the first clock information comprises a first time stamp and a first clock compensation parameter; the first node synchronizes a local clock according to the first clock information; and the first node sends second clock information to a third node, wherein the second clock information comprises a second time stamp and a second clock compensation parameter, and the second time stamp is the first time stamp or the second time stamp is a time stamp determined by the first node according to the first clock information.

[0115] The embodiment of the present application further provides a computer program product, comprising a computer program, which, when executed by a processor, implements a clock synchronization method. The method comprises the following steps: a first node receives first clock information sent by a second node, wherein the first clock information comprises a first time stamp and a first clock compensation parameter; the first node synchronizes a local clock according to the first clock information; and the first node sends second clock information to a third node, wherein the second clock information comprises a second time stamp and a second clock compensation parameter, and the second time stamp is the first time stamp or the second time stamp is a time stamp determined by the first node according to the first clock information.

[0116] In the embodiment, the storage medium can include, but is not limited to, a U disk, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store program codes.

[0117] Those of ordinary skill in the art will realize and understand that all or some of the steps in the methods disclosed above and the functional modules / units in the systems and devices can be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementation, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component can have multiple functions, or one function or step can be performed by several physical components in cooperation. Some or all of the components can be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on computer-readable media, which can include computer storage media (or non-transitory media) and communication media (or transitory media). As is well known to those of ordinary skill in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Furthermore, it is common and well understood by those of ordinary skill in the art that communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and can include any information delivery media.

Claims

1. A clock synchronization method, comprising: The first node receives the first clock information sent by the second node, the first clock information including a first timestamp and a first clock compensation parameter; The first node synchronizes its local clock according to the first clock information; The first node sends second clock information to the third node. The second clock information includes a second timestamp and a second clock compensation parameter. The second timestamp is the first timestamp or the second timestamp is a timestamp determined by the first node based on the first clock information.

2. The method according to claim 1, wherein, The first clock compensation parameter includes at least one of the following: a first timestamp reference time, a first clock compensation value, and a first clock frequency ratio; The second clock compensation parameter includes at least one of the following: a second timestamp reference time, a second clock compensation value, and a second clock frequency ratio.

3. The method according to claim 2, wherein, In response to determining that the first clock compensation parameter includes the first timestamp reference time, it indicates that the first timestamp is the timestamp of the first timestamp reference time; In response to determining that the first clock compensation parameter does not include the first timestamp reference time, it indicates that the first timestamp is the timestamp of the moment when the first clock information was sent; In response to determining that the second clock compensation parameter includes the second timestamp reference time, it indicates that the second timestamp is the timestamp of the second timestamp reference time; In response to determining that the second clock compensation parameter does not include the second timestamp reference time, it indicates that the second timestamp is the timestamp of the moment when the second clock information was sent.

4. The method according to claim 2, wherein, The first clock compensation value includes the clock message dwell time within the node between the time of the first timestamp and the second node; The second clock compensation value includes the clock message dwell time within the nodes between the time of the second timestamp and the first node.

5. The method according to claim 4, wherein, Based on one of the configuration signaling, pre-configuration signaling, and dynamic indication signaling, the following characteristics are determined: The first clock compensation value also includes the link propagation delay between the time of the first timestamp and the second node, or the first clock compensation value also includes the link propagation delay between the time of the first timestamp and the first node. The second clock compensation value also includes the link propagation delay between the time of the second timestamp and the first node, or the second clock compensation value also includes the link propagation delay between the time of the second timestamp and the third node.

6. The method according to claim 4 or 5, wherein, The first node synchronizes its local clock based on the first clock information, including one of the following: The first node synchronizes its local clock reference time based on at least one of the first timestamp, the first clock compensation value, and the link propagation delay between the second node and the first node. The first node receives the first clock information at the time it synchronizes its local clock based on at least one of the first timestamp, the first clock compensation value, and the link propagation delay between the second node and the first node. The first node synchronizes the local clock reference time based on at least one of the first timestamp and the first clock compensation value, the local time difference of the first node, the first clock frequency ratio, the clock frequency ratio between the second node and the first node, and the link propagation delay between the second node and the first node, and the time difference at any time after synchronizing the local clock reference time. The local time difference of the first node is the time difference between any time after the local clock reference time determined by the first node based on the local clock and the local clock reference time. The first node synchronizes its local clock with at least one of the following: the first timestamp and the first clock compensation value, the first node's local time difference, the first clock frequency ratio, the clock frequency ratio between the second node and the first node, and the link propagation delay between the second node and the first node, for any time after receiving the first clock information. The first node's local time difference is the time difference between any time after receiving the first clock information locally, as determined by the first node based on its local clock, and the time when it received the first clock information locally.

7. The method according to claim 6, wherein, The first node performs one of the following operations based on one of the following signaling methods: configuration signaling, pre-configured signaling, predefined rules, and dynamic signaling: Methods for determining the time of the local clock reference time, methods for determining the time of receiving the first clock information under the local clock synchronization, methods for determining the time of any time after the local clock reference time, and methods for determining the time of any time after the time of receiving the first clock information under the local clock synchronization.

8. The method according to claim 6, wherein, The first node synchronizes its local clock according to the first clock information, including: The first node synchronizes its local clock based on the first timestamp and the ratio of the first clock compensation value to the first clock frequency. Wherein, the first clock frequency ratio is the ratio of the clock frequency of the network master clock node to the clock frequency of the first node, or the first clock frequency ratio is the ratio of the clock frequency of the network master clock node to the clock frequency of the second node; the second clock frequency ratio is the ratio of the clock frequency of the network master clock node to the clock frequency of the first node, or the second clock frequency ratio is the ratio of the clock frequency of the network master clock node to the clock frequency of the third node.

9. The method according to claim 8, wherein, The content of the first clock frequency ratio or the second clock frequency ratio is determined based on configuration signaling, pre-configuration signaling, or dynamic indication signaling.

10. The method according to any one of claims 1 to 9, wherein, The first timestamp is one of the following: the original timestamp representing a specific reference time sent by the network master clock node, the timestamp at the moment when the second node transmits the first timestamp after completing clock synchronization, or the timestamp at the specific reference time after the second node completes clock synchronization; The second timestamp is one of the following: the original timestamp representing the specific reference time sent by the network master clock node, the timestamp at the moment when the first node transmits the first timestamp after completing clock synchronization, or the timestamp at the specific reference time after the first node completes clock synchronization.

11. The method according to any one of claims 1 to 10, wherein, The first node receives first clock information sent by the second node, including: The first node receives the first clock information sent by the second node via a first signaling message. The first node sends second clock information to the third node, including: The first node sends a second clock message to the third node via a second signaling method; Wherein, the first signaling or the second signaling is a Media Access Control (MAC) CE signaling or a Radio Resource Control (RRC) signaling.

12. The method according to claim 11, wherein, The first signaling or the second signaling is any one of broadcast signaling, multicast signaling, or unicast signaling. The first signaling is sent periodically or triggered by the first node, and the second signaling is sent periodically or triggered by the third node.

13. A clock synchronization device, disposed at a first node, comprising: The receiving module is configured to receive first clock information sent by the second node, wherein the first clock information includes a first timestamp and a first clock compensation parameter; The synchronization module is configured to synchronize the local clock of the first node according to the first clock information; The sending module is configured to send second clock information from the first node to the third node. The second clock information includes a second timestamp and a second clock compensation parameter. The second timestamp is either the first timestamp or a timestamp determined by the first node based on the first clock information.

14. A clock synchronization device, comprising: The memory is configured to store a program. The processor is configured to execute a program, which, when executed, performs the clock synchronization method as described in any one of claims 1 to 12.

15. A non-volatile storage medium comprising a stored program that, when executed, performs the clock synchronization method according to any one of claims 1 to 12.

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